The Russian prime minister, Vladimir Putin, has given the first signal that he might be prepared for dialogue with opposition groups but said they would have to form a proper bloc with a political platform first.

"There should be a dialogue, but what form it takes – I'm thinking about that," he told journalists at a year-end press conference on Wednesday. "They should come together with some form of joint platform and joint positions so we can understand what these people want. They are very different."

Referring to an anti-government protest on Saturday that snowballed into the largest ever manifestation of discontent with his 12-year rule, he said: "You had some people from [the] Yabloko [party], Communists, to some extent people from the nationalist movement, liberals.

"Was there a joint platform? No there wasn't. Who should we talk with? We should discuss all of their claims, their problems, but this will need some common sense."